With the increasing requests of human intelligent life, the increasing requirements of developing intelligent products, and the growing of Internet of Things (IoT), the requirements of data transmission and processing are increasing day by day. In a centralized data processing center, servers are key elements and have motherboards including CPU, chipsets, and memories, such as digital chips for data processing with power supplies and necessary peripheral elements. For increasing the processing capacity of servers in a unit volume, the number of digital chips and the density of integration are increased correspondingly. Consequently, the ratio of occupied space and power loss are increased. Therefore, the power supply (also called as motherboard power due to that the power supply and the digital chips are disposed on the same motherboard) employed by the system for providing power to the digital chips is expected to have higher efficiency, higher power density and smaller occupied space, so as to facilitate the entire server and even the entire data center to save energy and minimize the occupied area.
Generally, the power with the low voltage and the large current is provided to the digital chips mentioned above. For reducing the influences of power loss and impedance of the output wire, power supplies which are capable of providing power to the digital chips directly are disposed on the motherboard and located as close as possible to the digital chips. Therefore, the power supply which is capable of providing power to the digital chips directly is called as a point of the load (POL) power supply. The above-mentioned power supply has an input power provided from other power source. The typical POL power supply has an input voltage about 12 volts.
On the other hand, for achieving the applications in a distributed portable data processing terminal, the constituent elements and the digital chips have to be integrated into a small space and keep working for a long time. In addition, lower operating voltage is provided to the constituent elements and the digital chips. Generally, the lower operating voltage is provided by an energy storage device such as 3V to 5V battery. Therefore, the power supply tends to be requested with a high efficiency and a high power density.
At present, in a low-voltage DC/DC converter, a buck converter is usually employed to provide various output voltages ranged from 0 volt to 5 volts for the corresponding digital chips. FIG. 1 shows a circuit diagram of a typical buck converter. As shown in FIG. 1, the buck converter includes an input filter capacitor Cin, a main switching element Q1, an auxiliary switching element Q2, an inductor L and an output capacitor Co. The input filter capacitor Cin is electrically connected with a power source for receiving an input voltage Vin. The main switching element Q1 performs a turn-on and turn-off operation to adjust the output voltage Vo and the output current Io. The output current Io of the buck converter is provided to a load RL, i.e. the digital chip or a CUP.
However, in the above circuit, the ratio of the power loss and the occupied space of the inductor L to that of the entire converter is high. It is considered an important prerequisite to provide a magnetic assembly with high efficiency and high space utilization in order to achieve the purpose of optimizing the system with high efficiency and high powder density. At present, iron powder core, low temperature co-fired ceramic (LTCC) core or ferrite core is employed in the typical inductor. However, the inductor with iron powder core has higher power loss and is not suitable to be implemented in high-efficiency applications. Due to the limitation of the lamination process, the thickness of the metallic winding layer is thin, and the circulating capacity is limited. Consequently, the inductor with low temperature co-fired ceramic core can be implemented in a low-current application merely. The inductor with ferrite core has two types. One type of the inductor has a winding disposed in a window of the magnetic core. Under this circumstance, assembly tolerance exists and the issue of space caused due to the R angle around the magnetic core for installing the winding is a waste of space. Consequently, the space utilization of the inductor is reduced.
Therefore, there is a need of providing a magnetic assembly and a power module using the same in order to overcome the drawbacks encountered by the prior art.